1. Field of the Invention
The invention relates to a surgical stapler for anastomosis. More particularly, the invention relates to an intraluminal surgical stapler providing for the creation of an elliptical profile during anastomosis.
2. Description of the Prior Art
Surgical staplers have long been known in the surgical art as a quick and efficient way of joining or repairing tissue. Stapling has become an acceptable alternative to suturing. In certain types of surgical procedures, the use of surgical staples has become the preferred method of joining tissue and specially configured surgical staplers have been developed for these applications.
Intraluminal, or circular, staplers, have been developed for use in surgical procedures known as anastomosis. An example of an intraluminal surgical stapler used in performing anastomosis is disclosed in U.S. Pat. No. 5,104,025, which is incorporated herein by reference.
Conventional intraluminal surgical staplers typically include an elongated shaft having a proximal actuating mechanism and a distal stapling mechanism mounted to the shaft. The distal stapling mechanism typically includes a fixed stapling cartridge containing a plurality of staples configured in a concentric circular array. A round cutting knife is concentrically mounted in the cartridge interior to the staples. The knife is moved in an axial, distal direction during operation. Extending axially from the center of the cartridge is a trocar shaft. The trocar shaft is movable axially, with respect to the cartridge. An anvil member is mounted to the trocar shaft. The anvil member has a conventional staple anvil surface mounted to it for forming the ends of the staples. The distance between the distal face of the staple cartridge and the staple anvil surface can be controlled by an adjustment mechanism mounted to the proximal end of the trocar shaft. The tissue contained between the staple cartridge and the staple anvil surface is simultaneously stapled and cut when the actuating mechanism is triggered by the surgeon.
As briefly discussed above, an anastomosis involves a surgical procedure wherein sections of intestine are joined together after a connecting section has been excised. The procedure requires joining the ends of two tubular sections together to form a continuous tubular pathway. Prior to the introduction of intraluminal surgical staplers, the surgical procedure was a laborious and time-consuming procedure. The surgeon had to precisely cut and align the ends of the intestine and maintain the alignment while joining the ends of the tubular sections with numerous suture stitches. The development of intraluminal surgical staplers has greatly simplified the anastomosis procedure and also decreased the time required to perform an anastomosis.
When performing an anastomosis using an intraluminal surgical stapler, the intestine is typically stapled using a conventional surgical stapler with double rows of staples being positioned on either side of the target section of intestine. After removing the specimen, the surgeon typically inserts the anvil of the intraluminal surgical stapler into the proximal end of the lumen, proximal of the staple line. This is done by inserting the anvil into an entry port cut into the proximal lumen by the surgeon. On occasion, the anvil can be placed transanally by placing the anvil on the distal end of the stapler and inserting the instrument through the rectum. The surgeon then ties the proximal end of the intestine to the anvil shaft using a suture or other conventional tying device. The surgeon then cuts excised tissue adjacent to the tie and the surgeon attaches the anvil to the trocar shaft of the intraluminal surgical stapler. Next the surgeon closes the gap between the anvil and cartridge, thereby engaging the proximal and distal ends of the intestine in the gap. The surgeon next actuates the intraluminal surgical stapler causing several rows of staples to be driven through both ends of the intestine thereby joining the ends and forming a tubular pathway. Simultaneously, as the staples are driven and formed, a concentric circular blade is driven through the intestine tissue, cutting the ends adjacent to the inner row of staples. The surgeon then withdraws the stapler from the intestine and the anastomosis is complete.
By creating the staple line of the newly formed lumen along a plane perpendicular to the longitudinal axis of the lumen, substantial stresses occur within the lumen. In particular, material passing through the lumen is confronted with all edges of the staple line simultaneously. This results in great stresses along the staple line. In addition, the strength of the staple line is limited by the diameter and, thus the circumference, of the lumen at the point of the staple line.
With this in mind, a need currently exists for a mechanism that optimizes the strength and functionality of a staple line created by an intraluminal surgical stapler. The present invention provides such an apparatus.